My "pensive" - where i simply siphon the excess thoughts from my mind, pour them into the basin (of cloud storage), and examine them at leisure.

Sunday, April 06, 2014

CAP Theorem

Proposed by Eric Brewer. States
that it is impossible for adistributed
computer systemto
simultaneously provide all three of the following guarantees:

Consistency – all nodes see the same data at the same timeAvailability – a guarantee that every request receives a response about whether it was successful or failedPartition tolerance – the system continues to operate despite arbitrary message loss when network is partitioned.

CA = If network is partitioned, the nodes continue to be
available by themselves and data continues to be consistent on the same node
even when there is no partition tolerance.

AP = Nodes may still be available even when we ensure
partition tolerance by disallowing further writes but data will not remain
consistent between the nodes anymore as nodes cannot exchange message due to
network partitioning.

PC = Nodes may be consistent but in order to ensure
partition tolerance they may not be available to write.